The present invention relates to movement detectors such as are used in apnea monitors, and also to an apnea monitor including such a detector.
Apnea monitors are used to detect a cessation of breathing (apnea) in infants in order to prevent sudden infant death (SID), which may occur while the infant is asleep. Many types of apnea monitors have been developed for this purpose. One type includes movement detectors, such as piezoelectric crystal transducers which detect the breathing movements of the infant. Examples of the latter type movement detector are described in U.S. Pat. Nos. 4,169,462, 4,576,179, 4,657,026 and Re 32,180. As a rule, however, the known apnea detectors are either very expensive and therefore suitable only for hospital use and not for home use, or are characterized by high rate of false alarms so as not to be sufficiently reliable.